INTAKE, MILK-YIELD, AND DIGESTION BY DAIRY-COWS FED DIETS WITH INCREASING FIBER CONTENT FROM BERMUDAGRASS HAY OR SILAGE

Lactating dairy cows were offered diets containing increasing quantiti es of Tifton 85 bermudagrass hay or silage and increasing dietary neut ral detergent fiber (NDF) to determine effects of method of bermudagra ss storage and dietary fiber content on intake, milk yield, and nutrie nt digestion. Bermudagrass was added as hay or silage at the rate of 8 .5, 15.9, or 23.3% of dietary dry matter and was substituted for an eq ual quantity of corn silage. The method of bermudagrass storage did no t affect intake [20.8 vs. 20.3 (+/-0.3) kg/d for bermudagrass hay and silage diets; respectively], but an increase in the amount of bermudag rass and NDF in the diet did reduce intake. Dietary NDF concentration was well above minimum recommendations of the National Research Counci l. Milk yield was not altered by method of bermudagrass storage but de clined as dietary NDF increased. Digestion of NDF tended to be lower f or bermudagrass silage than for bermudagrass hay. An increase in the a mount of bermudagrass in the diet improved digestion of dietary dry ma tter, acid detergent fiber, and NDF; however, milk yield declined beca use total intake declined. Improved NDF digestion caused by added berm udagrass hay or silage was confirmed by in vitro analyses. High qualit y bermudagrass hybrids could potentially be used in diets of lactating dairy cows because of the good digestion characteristics and relative ly small effects on intake despite the high dietary fiber content. Tif ton 85 bermudagrass may Serve as a forage alternative for lactating da iry cows.